The present invention has been derived from research undertaken as a part of the information technology (IT) R & D program of the Ministry of Information and Communication and Institution of Information Technology Association (MIC/ITTA) [2006-S-004-02], silicon-based very high speed optical interconnection IC.
As a semiconductor industry is developed, semiconductor integrated circuits such as a logic device (e.g., a central processing unit or a graphic processing unit etc.) and a memory device become faster more and more. However, a communication speed between the semiconductor integrated circuits may have its limitation. Typically, the semiconductor integrated circuits may exchange data and/or signal through an electrical communication that electrically transmits and receives data and/or signal. For example, the semiconductor integrated circuits may be mounted on a printed circuit board and may perform an electrical communication through wirings in the printed circuit board. In this case, there may be limitations in reducing an electrical resistance (e.g., a resistance between a pad of a semiconductor integrated circuit and an external terminal of a package, a contact resistance between a package and a printed circuit board and/or a wiring resistance of a printed circuit board) between the semiconductor integrated circuits. Additionally, an electrical communication may be affected by external electromagnetic waves. Due to the above factors, it is difficult to increase a communication speed between the semiconductor integrated circuits.
Recently, an optical communication was suggested as one plan for improving a communication speed between semiconductor integrated circuits. The optical communication may transmit and receive an optical signal where information is stored. The optical communication may reduce interference of external electromagnetic waves, compared to the electrical communication, and also can process a large amount of data simultaneously.
Among the semiconductor integrated circuits, an electrooptic device is used for an optical communication and/or an optical connection that connects optical signals. Some of the electrooptic devices convert a phase of an optical signal. A phase of an optical signal may be an important factor determining data stored on the optical signal. Therefore, an electrooptic device for changing a phase of an optical signal may deliver an optical signal or convert an optical signal into an electric signal.
Recently, as industry is highly developed, demands for high speed, low power consumption, and/or miniaturization of electronic products including semiconductor integrated circuits are gradually increased. Accordingly, research for improving characteristics of an electrooptic device has been actively under development.